diff --git a/README.md b/README.md
index 5b3194f..33ca254 100644
--- a/README.md
+++ b/README.md
@@ -70,12 +70,13 @@ wget https://bfd.mmseqs.com/bfd_metaclust_clu_complete_id30_c90_final_seq.sorted
 mkdir -p bfd
 tar xfz bfd_metaclust_clu_complete_id30_c90_final_seq.sorted_opt.tar.gz -C ./bfd
 
-# structure templates (including *_a3m.ffdata, *_a3m.ffindex)
+# structure templates [81G] (including *_a3m.ffdata, *_a3m.ffindex)
 wget https://files.ipd.uw.edu/pub/RoseTTAFold/pdb100_2021Mar03.tar.gz
 tar xfz pdb100_2021Mar03.tar.gz
 ```
 
-8. Download BLAST
+8. Download BLAST [39M]
+
 ```
 wget https://ftp.ncbi.nlm.nih.gov/blast/executables/legacy.NOTSUPPORTED/2.2.26/blast-2.2.26-x64-linux.tar.gz
 mkdir -p blast-2.2.26
diff --git a/rf2aa/data/parsers.py b/rf2aa/data/parsers.py
index 86f8ac0..f402151 100644
--- a/rf2aa/data/parsers.py
+++ b/rf2aa/data/parsers.py
@@ -227,7 +227,7 @@ def parse_multichain_fasta(filename,  maxseq=10000, rna_alphabet=False, dna_alph
 
     # convert letters into numbers
     if rna_alphabet:
-        alphabet = np.array(list("00000000000000000000-000000ACGTN"), dtype='|S1').view(np.uint8)
+        alphabet = np.array(list("00000000000000000000-000000ACGUN"), dtype='|S1').view(np.uint8)
     elif dna_alphabet:
         alphabet = np.array(list("00000000000000000000-0ACGTD00000"), dtype='|S1').view(np.uint8)
     else: